Method for assembling cross braces on a multi-leg tower



March 3, 1964 v I. D. ROHN 3,122,819

METHOD FOR AS SEMBLING CROSS BRACES ON A MULTI-LEG TOWER Original Filed July 26, 1955 4 Sheets-Sheet 1 A TTORNEYS March 3, 1964 1. D. ROHN I 3,122,819

METHOD FOR ASSEMBLING CROSS BRACES ON A MULTI-LEG TOWER Original Filed July 26, 1955 4 Sheets-Sheet 2 III/ll/IIA INVENTOR. /K4A/ 0w/4wr Pay/V I BY w AZ /kfi RNEYS March 3, 1964 l. D. ROHN 3,122,819

METHOD FOR ASSEMBLING CROSS BRACES ON A MULTI-LEG TOWER Original Filed July 26, 1955 4 Sheets-Sheet 5 EIE- '1 5i TTOR March 3, 1964 D. ROHN 3,122,819

METHOD FOR ASSEMBLING CROSS BRACES ON A MULTI-LEG TOWER Original Filed July 26, 1955 4 Sheets-Sheet 4 "H 5 V ATTORNH:

United States Patent 3,122,819 METHOD FUR ASSEMBLING CRGSS BRACfi ON A MIJL'II-LEG TOWER Ivan Dwight Rohn, Peoria, Ill. (R.F.D., Washburn, Ill.)

()riginal application July 26, 1955, Ser. No. 524,345, new Patent No. 3,021,885, dated Feb. 2%), B62. Divided and this application June 20, 1961, Ser. No. 118,362

4 Claims. (Cl. 29-155) This invention relates to a method for assembling cross braces on a multi-leg tower or the like.

The present application is a division of my parent application entitled Apparatus for Assembling Cross Braces on a Multi-Leg Tower. This application was filed on July 26, 1955 and issued as Patent No. 3,021,885 on February 20, I962.

At the present time there is a huge demand for various types of towers and more particularly light weight towers for use by television and radio owners in areas where good reception requires an elevated aerial. Due to the fact that different areas require different heights for the tower, in order to attain good reception and for reasons of ease of assembly, it is contemplated that the tower be composed of a plurality of reinforced light weight sections.

It is therefore an object of the present invention to provide a novel method for forming and assembling cross braces on a multi-leg sectioned tower capable of meeting the demands of the public for a sturdy light weight tower.

Another object of this invention is to provide a novel method and apparatus for forming and assembling cross braces on a multi-leg tower which permits large scale production techniques to be utilized at the lowest possible cost.

Still another object of the present invention is to provide a method for facilitating formation of and assembly of cross braces on a multi-leg sectioned tower.

Other objects, features and advantages of the present invention will be more readily apparent from the following detailed description of the drawings illustrating a single embodiment thereof, in which:

FIGURE 1 is a front elevation of an apparatus utilized in the method assembling the cross braces on the tower;

FIGURE 2 is a fragmentary cross sectional view taken on the line lI-II of FIGURE 1 showing the straps or blanks in place and one upright laying across same to be clenched thereto;

FIGURE 3 is a side elevation showing in full and dotted lines how the cross brace is attached to the leg or upright; I

FIGURE 4 is a fragmentary side elevation similar to FIGURE 3 showing a subsequent step in my invention;

FIGURE 5 is an enlarged fragmentary sectional view through FIGURE 3 showing in greater detail how the strap blank is attached to the upright;

FIGURE 6 is an enlarged fragmentary sectional View similar to FIGURE 5 only showing a subsequent step of my invention;

FIGURE 7 is a fragmentary front View showing the formed tower with apparatus thereon to facilitate the welding operation;

FIGURE 8 is an enlarged fragmentary View of the clamp and end jig shown in FIGURE 7;

FIGURE 9 is an enlarged cross sectional view taken substantially on the line IX-IX of FIGURE 8 looking in the direction indicated by the arrows;

FIGURE 10 is an enlarged fragmentary perspective view showing a portion of the completed tower;

FIGURE 11 is an enlarged fragmentary cross sectional view taken on the line XIXI of FIGURE 3 looking in the direction of the arrows;

FIGURE 12 is an enlarged elevation of a strut or brace blank; and

FIGURE 13 is an enlarged cross sectional view taken substantially on the line XIIL-XIII of FIGURE 12 looking in the direction indicated by the arrows.

As shown on the drawings:

The reference numeral 10 (FIG. 3) indicates generally an anchored press or break machine which is operated by a motor 11 connected to a V-belt drive 12 for driving an eccentric 13. Connected to the eccentric 13 are two vertical moving rams I4 and 15 (FIG. 1) which are joined at their lower vertical ends by means of a pivotal connection (FIG. 1) to a hold-down member 16. The holddown member is movable vertically relative to the press 10 and is guided in its vertical movement by means of dovetail connection Illa (FIG. 11) between the holddown member 16 and press 10. Affixed on the vertically underside of the hold-down member 16 are suitably eight spaced vertically movable plungers 17.

Joined to the press 10 just below the plungers 17 are a plurality of sets or pairs of spaced generally horizontally extending fixedly mounted arms and members which are all identical in construction. The arms 18 and 19 are bridged between and fixedly connected to the frame 10 and vertically extending spaced anchor supports 20 and 21. The supports 20 and 21 and the frame 10 are engaged with opposite ends of the pairs of arms 18 and 19 and serve to maintain the arms in a stationary position. Pivots 22 are provided between each of the pairs of the arms 13 and 19 and lever arm or member 23 enabling the lever arm to be rocked on the pivots 22 when one end of the lever arm is engaged and actuated by the plunger 17 or actuator. Each of the arms 23 is provided with a die or a clenching die structure or a strap and rod supporting and strap clenching die area which is indicated generally at 24 and is disposed generally on the outer side of the arm 23.

It will be best seen in FIGURES 1 and 3 that a plurality of spaced pivotally mounted arms 23 are illustrated which together with the other apparatus define eight separate stations. Each of the stations is capable of receiving a cross brace blank 25 (FIGS. 12 and 13) which is to be formed in the die 24 in the assembly of same upon the tower indicated generally at 26 in FIGURE 10. The tower is preferably of a tripodal construction having spaced tubular legs 27. More than three legs 27 may be used, if desired, but a tripodal type tower is the least expensive to manufacture.

The cross brace blanks 25 are each of a reinforced more or less M-shaped transverse cross section (FIG. 13) having at spaced intervals of the blank along the length flat portions 28 (FIGS. 5 and 12) which are to be deformed to engage nestingly about the rods 27 as hereinafter will become more apparent. The number of these fiat portions 28 depends of course upon the number of legs 27 in the tower 26. If a tower having three legs is to be manufactured then two fiat portions 28 are employed to engage two of the legs 27 and the ends 25a and 25b of the blanks 25 are engaged with and secured to the third leg 2 as shall become more evident hereinafter.

Each of the dies 24 (FIGS. 5 and 6) on the lever arms 23 includes a recess 29 having a vertically slidable spring tensioned anvil 30 adjustably mounted therein. The lower end of the recess 29 leads into a slot 31 which is adapted to receive a bolt 32 having a spring 33 therearound in the recess. The bolt 32 is attached to a nut at one end with the other end bearing against the anvil for adjusting the level of the anvil with the top surface Q of the arm 23 whereby the brace or strap blank 25 may be maintained in engagement against the tubing 27 during the clenching operation.

. Mounted on the arm 23 on opposite sides of the recess 29 are protuberances 35 and 36 which serve to aid in centering a fiat portion 28 of the brace or strut relative to the die (FIGS. and 6). By so doing, the uprights may be equidistantly spaced from one another since the flat portions 28 on the blanks are'evemy spaced.

The anvil has an arcuate indentation or a die bottom 37 which is a component of the die 24 and aids in the forming and assembly of the brace blanks 25 on the rods 27. In addition, spaced corners or strap forming or bending edges 38 and 39 at the vertically upper end of the recess 29 define edges along with the vertical side walls for further aiding in the formation and assembly of the braces on the rods (FIGS. 5 and 6). The stationary arms 19 have notched ends or areas or channeled rod gripping areas 46 closely approximating the cross sectional configuration of the rods 27. i

In the formation of the tower section the arms 18 and 19 function as one leg of a scissor structure with the lever arms 23 being movable relative to the stationary arms 18 and '1? by the operation of the actuator structure which includes the press 10 as well as the hold-down member 16 and the plunger 17. The actuator structure provides means on the apparatus to cause relative movement between the scissor first and second legs to clench the straps to the rod or upright. When the second leg of the scissor structure is actuated the upright is forced against the one leg of the scissor structure the straps are caused to be bent and deformed about the upright by means of the dies 24 which are spaced along the second leg of the scissor structure.

Method of Operation The first step in the operation of my novel apparatus is to insert the cross brace blanks 25 in this case eight of them although any suitable number may be employed, upon the horizontally spaced receiving stations of the machine. The flat or corner portion 28 of each blank is centered with relation to the protuberances and 36 at each station so that the portion 28 is vertically aligned with the die recess 29 (FIG. 3).

Thereafter a rod is transversely positioned across all eight of the support strap blanks 25 and in each instance is rested upon a flat portion 29 of each blank. It will be noted that a centering jig 41 (FIGS. 1 and 2) is secured to the press and carried at one end of the row of stations by one of the arms 18 so as to center the rod 27 relative to the supported blanks 25. The jig 41 has three stops 42 against which each of the tubular ends of the rods 27 are adapted to bear against in the progressive assembly of the three legs 27 and the strap blanks thereby insuring proper alignment of the ends of the legs.

At this point the anvil 3% may be adjusted to keep the brace blank 25 firmly tensioned against the tubing 27 during the clenching operation (FIG. 6).

The next step is to start the machine with the plungers 17 urg ng one end of each of the lever arms 23 downward and thereby urging the other end of the arm having the die 24 vertically upward to forcibly press the leg 27 against the notched area of the stationary arm 19. As a consequence of the leg or rod 27 striking the arms 18 and 19, the force of the impact causes the flat portion 28 to be nested or clenched more than half way around the rod to firmly grip and clench same (FIG. 6). It will be appreciated the preferred manner of operation is one where the clenching action occurs simultaneously at all of the stations.

The operator of the machine then picks up the rod 27 and attached brace links 25 and manually rotates or in dexes the assembly (FIG. 4) by sliding same rearwardly toward the press so that the next set of flat portions 28 of the strap blanks are aligned with the dies 24. A secr 4.- ond rod or upright is transversely aligned by means of jig 41 and disposed over the dies 24 so that it rests on the flat portions of the straps 25. The plungers 17 are again activated to clench the second rod to the brace blanks 25 in the same manner as previously.

The operator then indexes or rotates the assembly again. The free ends 25a and 2512 (FIG. 9) of each of the braces 25 are then aligned end to end and the third rod is properly positioned with respect to the other rods already clenched to the braces by means of the jig 41. Again the plungers 17 are activated and the end portions 25a and 25b are deformed so as to nest about the rod.

In order to insure more reinforced connections between the rods and the formed cross braces 43, each of the formed braces 43 where engaged with the rods 27 may be welded to the rods. To aid in this operation jigs 44 and 35 (FIG. 8) are utilized. HG 44- (PliG. 8) comprises a main tni-pod-al base 46 provided with three tubular extensions 47 each having a female terminal 48. Since the rods 27 have male terminals 4-9 with reduced diameters to facilitate in the vertical stacking of same, they may be readily inserted into the female terminals 48 and maintained in aligned position by means of a pin 51 through the male and female terminals.

Jig comprises a bar 51 having spaced clip like clamps 53. at intervals thereon. These spaced clamps 5.2 are each engaged over the free ends 25a and 25b to hold same in tight engagement with the rod 27 (FIGS 7-9).

The final step in my novel method is to weld or otherwise secure each of the points of contact between the rods 27 and the nested portions of the cross braces 43. Any suitable welding equipment may be used to weld the assembled tower braces and legs while they are held in the jigs 44 and 45 above described. Thereafter these jigs are removed from the completed tower section.

It will be understood that variations and modifications may be effected without departing from the novel concepts of the present invention.

I claim as my invention:

1. In a method of forming and assembling a plurality of spaced longitudinal rods with transversely extending metal straps disposed along the length of said rods to form an enclosed tower section, the steps of disposing a rod on a series of spaced generally straight straps, contemporaneously angularly bending and clenching a portion of each strap to said rod by deforming each strap portion transversely around more than one half of the perimeter of each rod, indexing the rod and attached straps to position other portions of the straps to receive another rod,

angularly bending and clenching such other portions in like manner to a second rod, again indexing the straps and attached rods, deforming the end portions of each of the straps around another rod and fastening such end portions to said last mentioned rod.

2. In a method of forming and assembling transverse straps on a plurality of spaced longitudinal uprights to form an enclosed tower section, the steps of placing generally straight strap blanks into spaced forming stations, aligning and positioning an upright over all the stations and strap blanks therein, angularly bending and clenching the strap blanks to the upright by bending a portion of each of the blanks to grip the upright, indexing the partially formed assembly to position other portions of the straps relative to another upright, angularly bending and clenching such other portions in like manner to an upright, again indexing the assembly, deforming the end portions of each of the straps around another upright and fastening such end portions together. 7

3. In a method of forming and assembling a plurality of spaced longitudinal rods with generally straight trans,

versely spaced metal straps to form an enclosed tower section, the steps of dis-posing a rod on a series of gen era-lly straight transversely spaced straps, contemporaneously angularly bending and clenching a portion ofeach strap to said rod by deforming each strap portion transversely around only a portion of the perimeter of each rod, indexing the rod and attached straps and repeating the above stepsuntil the straps are angularly bent and clenched to at least three rods, and fastening end portions of each of the straps together to form a tower section.

4. The method of forming an enclosed tower section by engaging a first upright with a series of generally straight transversely spaced strut elements extending transversely of the upright, angularly bending and clenching the transverse strut elements to the first upright, engaging a second upright with the transverse strut elements spaced from the first upright and angularly bending and clenching the transverse strut elements to the second upright, and securing the thus bent areas of the transverse strut elements to the uprights and securing the ends of each of the transverse strut elements to still another upright.

References Cited in the file of this patent UNITED STATES PATENTS 302,806 Wheatley July 29, 1884 798,730 Johnson Sept. 5, 1905 969,859 Haskell Sept. 13, 1910 1,692,033 Gray Nov. 20, 1928 2,877,008 De 'Mattia et al Mar. 10, 1959 2,940,162 Sandberg June 14, 1960 

1. IN A METHOD OF FORMING AND ASSEMBLING A PLURALITY OF SPACED LONGITUDINAL RODS WITH TRANSVERSELY EXTENDING METAL STRAPS DISPOSED ALONG THE LENGTH OF SAID RODS TO FORM AN ENCLOSED TOWER SECTION, THE STEPS OF DISPOSING A ROD ON A SERIES OF SPACED GENERALLY STRAIGHT STRAPS, CONTEMPORANEOUSLY ANGULARLY BENDING AND CLENCHING A PORTION OF EACH STRAP TO SAID ROD BY DEFORMING EACH STRAP PORTION TRANSVERSELY AROUND MORE THAN ONE HALF OF THE PERIMETER OF EACH ROD, INDEXING THE ROD AND ATTACHED STRAPS TO POSITION OTHER PORTIONS OF THE STRAPS TO RECEIVE ANOTHER ROD, ANGULARLY BENDING AND CLENCHING SUCH OTHER PORTIONS IN LIKE MANNER TO A SECOND ROD, AGAIN INDEXING THE STRAPS AND ATTACHED RODS, DEFORMING THE END PORTIONS OF EACH OF THE STRAPS AROUND ANOTHER ROD AND FASTENING SUCH END PORTIONS TO SAID LAST MENTIONED ROD. 